If it’s 03 I don’t think it will be a PD engine… 😐
White smoke from a TDi Galaxy / Sharran / Alhambra is 99% the Auxilliary heater, under the passenger side rear wheel arch. It’s only supposed to try & work below 10degC though. They have a heater plug that burns out. If working fine should sound like a jet engine on a cold day.
For the clattering, watch the aux belt when someone starts the car from cold. They have a clutch type pulley on the alternator. These seize up, & can sometimes take a minute to free up from cold, but usually only when it’s idling. It allows the alternator to free wheel. The belt will be jumping around, but then run free. Sounds clattery while it’s bouncing. Alternator out to change, & a special tool to change. Several types of pulley, so count the teeth & measure dia before buying.
Other than that, the CAT, loose stuff in there bouncing around ?
Post this on FGOC.CO.UK
Daz or Serviceford are top blokes, & know these cars inside out.